tracing the relationships between sleep disturbances and symptoms of irritable bowel syndrome

background and objective : irritable bowel syndrome (ibs) is a functional gastrointestinal disorder. sleep disturb-ances are known to be common among individuals with this syndrome. this study aimed to determine the relationship between sleep quality and severity of intestinal symptoms in irritable bowel syndrome. materials and methods : this cross-sectional study was carried out among 201 subjects who met the rome iii criteria for irritable bowel syndrome with no organic gastrointestinal or mental disease. demographic data was recorded; pittsburgh sleep quality index (psqi) and irritable bowel syndrome severity scoring system (ibs-sss) questionnaires were employed to measure the sleep quality, hours of sleeping in darkness and severity of intestinal symptoms. the hospital anxiety and de-pression scale (hads) questionnaire was also used to measure the anxiety and depression among the subjects. results : among 201 subjects, 67.2% were poor sleepers (psqi > 5), and the average time for sleeping in darkness was 5.51 ± 1.45 hours. anxiety and depression were significantly related to the sleep quality. besides, the subjects with more hours of sleeping in darkness tended to have lower psqi scores. the correlation between the global ibs-sss and psqi score indicated a strong relationship (p = 0.02), which became weaker after adjusting the effects of anxiety and depression (p = 0.05). subjects with depression spent fewer hours to sleep in darkness and the mean hours of sleeping in darkness were lower in subjects with ibs symptoms compared to the group in remission. conclusion : there is an inverse relationship between the severity of symptoms of irritable bowel syndrome and sleep quality.